Abstract:
Contaminated soils arising from the petroleum industry remains a major problem globally,
resulting in levels of petroleum hydrocarbons and metals that are dangerous to the environment.
Modern remediation strategies focus on sustainability, thus maximizing environmental, social,
and economic benefits. The use of materials derived from agricultural and industrial waste, for
example biochar and spent mushroom compost (SMC), may provide a potential solution to
sustainable remediation strategies. Biochar has numerous properties, e.g., high surface area and
pore volume that may provide benefits to the remediation industry. SMC, a by-product of
mushroom production, may contain diverse groups of microorganisms and extracellular
enzymes important for the biotransformation of contaminants. Biochar and spent mushroom
compost interactions in soil may induces diverse responses in microbial species leading to
changes in soil enzyme activity, reshaping of microbial community structure and consequent
enhancement of contaminants transformations. However, the mechanisms underlying these
interactions are poorly understood, with unpredictable outcomes. There is a deficit of research
designed to understand their collective response on soil fungi and the subsequent benefits to
remediation success. Research needs to focus on the benefits of biochar towards affecting
contaminant bioavailability of multiple rather than single contaminants. Combining biochar
with SMC may facilitate the biodegradation of petroleum hydrocarbons in saline soils. The aim
of the research was to develop a biotechnological approach for the best use of biochar and SMC
to promote microbial remediation of soil contaminated with complex chemical mixture
contaminants (hydrocarbons and heavy metals). It provides a mechanistic understanding of the
physicochemical and biological parameters influencing the remediation approach. The study
further sheds light into the influence of low carbon soil amendment on the behaviour and fate
of heavy metal(loids) and petroleum hydrocarbons, and the underlying microbial community
responses in a genuinely contaminated soil in a four-month microcosms study, and in crude oil
and salt spiked soil in another four-month microcosms study.
